Synthesis, characterization and dye adsorption studies of porous brookite and mixed brookite with rutile TiO2 using PEG assisted sol-gel synthesis process

Abstract

Titanium Di-Oxide (TiO2) was synthesized using PEG template assisted sol-gel synthesis process. Role of Poly ethylene Glycol (PEG) and the corresponding porous evolution was studied with respect to calcination temperatures. PEG evaporation and optimum pore formation was deduced from DTA, TGA and BET studies. Crystallization was studied using X-ray powder diffraction and Micro-Raman measurements. Field Emission Scanning Electron Microscope (FESEM) and HRTEM studies revealed that the porosity arises from the voids between the assemblies of nanocrystallites. Highest surface area of 133m2/g and 159m2/g were recorded for both brookite and brookite mixed with rutile respectively. The phase transition root was identified as: (i) from brookite to rutile and (ii) mixed brookite with rutile to pure rutile phases. Photodegradation studies reveal identical degradation sequence of MB>MO>RhB for brookite and P25 samples and a different degradation sequence of MB>RhB>MO for brookite mixed with rutile sample.